Combine the egg white, sugar, and vegetable oil in a bowl and mix well.
Add the cake flour and mix with a spatula until it comes together.
Divide into bite-sized pieces and roll into balls. Lightly press down on the tops.
Arrange on kitchen parchment paper with 1 cm between each piece and microwave at 600 W for 2 minutes. Keep an eye on them. If they seem to need more time, microwave for short increments until they're done.
Let cool and enjoy.
Note: During the warm season or other times when your room may be hot, let the dough chill in the refrigerator first and/or reduce the amount of vegetable oil to make shaping it easier.
Story Behind this Recipe
Whenever I make pasta carbonara, I have leftover egg whites. It's such a waste to just throw them out, so when I make carbonara, I make these simple cookies as well.
Depending on how long you cook them, you can have fluffy or crispy cookies But be careful not to let them burn! Once they start to turn brown, you've reached their limit.